Subcellular localization of 111In in human and rabbit platelets.
In order to examine the subcellular distribution of 111In in 111In-oxine-labeled human and rabbit platelets, we employed a hypothetical grain technique of EM autoradiography analysis. The results indicate that in the rabbit 111In was concentrated within the platelet dense bodies, particularly when the platelets had been labeled in a plasma-free system. Under comparable conditions of labeling, human platelets appeared to accumulate almost all the radiolabel within the cytosol. Using inhibitors of 5-hydroxytrptamine (5-HT) uptake, i.e., cloimipramine, ouabain, sodium fluoride, p-chloromercuribenzoate, and reserpine, we were unable to demonstrate an active uptake process in either species. Both collagen and thrombin were able to cause dose-dependent release of radioactivity from the labeled rabbit platelets only. In the case of collagen, this mimicked endogenous 5-HT release and was inhibited by indomethacin. These results and their implications are discussed.
D000818:Animals; D001345:Autoradiography / Q000379:methods; D001792:Blood Platelets / Q000000981:diagnostic imaging* / Q000648:ultrastructure; D006801:Humans; D066298:In Vitro Techniques; D007204:Indium; D008854:Microscopy, Electron; D015125:Oxyquinoline; D011817:Rabbits; D011868:Radioisotopes; D011877:Radionuclide Imaging; D013347:Subcellular Fractions / Q000000981:diagnostic imaging
D011868:Radioisotopes; D007204:Indium; D015125:Oxyquinoline